Operating a centrifugal separator involves consumption of energy, part of which is lost in the form of aerodynamic losses at the contact between the rotating parts, e.g. the rotor, and surrounding gas. These losses may thus cause unnecessarily high energy consumption of the centrifugal separator. The losses also contribute to warming of the rotating parts and of adjacent parts and material, e.g. said fluid for centrifugal separation. In many cases this warming is undesirable, particularly where fluids which are sensitive to thermal action are to be separated. A further problem with the warming is that the heat generated may have to be disposed of, which in many cases entails the centrifugal separator having to be provided with a cooling device, e.g. such a separator may be provided with a water-cooled casing.
DK 75995 C describes clarification of beer in a centrifugal separator in which the separation takes place in a separator bowl enclosed in an evacuated space. The object is to reduce the warming of the beer passing through the separator and thereby improve the clarification. The centrifugal separator described has a rotor of so-called solid wall type, which does not make it possible to discharge any separated components from the beer via outlets at the periphery of the rotor.
RU 2240183 C2 describes a centrifugal machine for cleaning of liquids which comprises a container of water in a space round the rotor, which water is caused to vaporise and form water vapour in the space round the rotor in order to reduce the aerodynamic losses during rotation. A wall is arranged to prevent separated material from moving out into the space round the rotor.